Pulp molding machine with molds forming an endless chain



J. M. POTTER June 22, 1965 PULP MOLDING MACHINE WITH MOLDS FORMING ANENDLESS CHAIN Filed Dec. 4, 1961 2 Sheets-Sheet 1 m a m 4 W WP elm 1 M gl 1 5 M 4T a N 3 WM B M 5 MY w 3,190,791 PULP MOLDING MACHINE WITH MOLDSFORMING AN ENDLESS CHAIN J. M. POTTER June 22, 1965 2 Sheets-Sheet 2Filed Dec. 4, 1961 INVENTOR. J4/7E5 P0775? BY 80% A U M50-u.

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United States Patent 3,196,791 PULP MGELDTNG MACHME WTTH MQLDS FORMINGAN ENDLESS CHAIN James M. Potter, Flagstaff, Ariz., assigner to BankersLife & Casualty Company, Chicago, TEL, a corporation of Illinois FiledDec. 4, 1961, Ser. No. 156,668

4 Claims. (til. 162-219) The present invention relates generally to pulpmolding and, more particularly, it relates to pulp molding apparatus inwhich molded articles are formed as an integral portion of a continuousweb.

Molded pulp articles comprise items formed from wood pulp or otherpulps. Well known examples of such molded pulp articles include eggcartons and pie plates.

Various means for forming molded pulp articles have been known and usedfor many years. The most common apparatus used for producing sucharticles comprises a rotating carrier provided with porous dies aroundits periphery. The dies are suitably contoured to provide the desiredshape for the article being molded.

A reservoir disposed beneath the carrier contains a quantity of stock,which is a suspension of the fibers from which the article is to beformed, and, as the carrier rotates, the dies are submerged in the stockfor a prede termined period or" time. Vacuum is applied through thesubmerged dies, thereby depositing the fiber of the exterior of the die;

One problem associated with pulp forming apparatus heretofore known hasbeen the difiiculty of handling individual wet pulp articles from theforming dies. A wet pulp article is structurally weak, and, if it is notcontinuously supported in the desired configuration, the article willtend to deform. Accordingly, it has heretofore been necessary to providesupport for each article until sufiicient water has been removedtherefrom to render it self-Supporting. This has required asubstantialinvestment in means for transporting the individual wet pulp articlesthrough drying means, and has imposed limitations on productive capacityof the apparatus.

It is a primary object of the present invention to provide improved pulpforming means. A more particular object of the present invention is toprovide pulp form ing means in which is formed a continuous web whichincludes molded pulp articles as an integral portion thereof. Otherobjects and advantages of the present invention will become apparentfrom the following description and drawings, in which:

FIGURE 1 is a schematic fragmentary elevational view, partly brokenaway, of apparatus suitable for the practice of the present invention;

FIG. 2 is a schematic fragmentary plan view, partly broken away, of theapparatus shown in FIGURE 1; and

FIGURE 3 is an enlarged perspective view of a portion of the conveyorwhich is a part of the apparatus illustrated in FIGURES l and 2.

In accordance with the present invention, there is provided appartus onwhich molded pulp articles are produced as an integral portion of acontinuous web. The web is partially dried on the apparatusand,thereafter, has suflicient strength to be handled without means forindividually supporting the molded pulp articles.

There is illustrated in FIGURE '1 pulp forming apparatus 5 whichcomprises a frame 7 fabricated from suitable beam and channel membersfor-carrying various components on the apparatus including a conveyor13. The conveyor'13 is trained around and between sectioned drums a,15b, and 150, and idler drums 17a and 17b. Stock reservoirs 19a, 19b,and 19c are also carried on the frame, and are located below each of thesectioned drums 15a, 15b, and 150. The stock reservoirs are suppliedwith stock from a chest (not shown) through a pipe 20. Level controlapparatus may be in each reservoir 1%, 19b, and 190.

The idler drums 17a and 1712 are disposed on the frame 7 between thesectioned drums 15a, 15b, and 150, and support the conveyor 13 in such amanner that the conveyor is in contact with the peripheral surface ofthe drums 15a, 15b, and 150, while it is immersed in the reservoirs 19a,19b, and 19c.

It will be seen that the longitudinal axes of the sectloned drums 15a,15b, and 15c are generally horizontal, and parallelto each other; withthe middle drum 15b having its axis below the axes of the drums 15a andso that the upper portion of the drum 15b does not interfere with theupper run of the conveyor 13 between drums 15aand 150. The longitudinalaxes of the idler drums 17a and 17b are parallel to the axes of thesectioned drums 15a, 15b, and 15a and are on a level with drums 15a and150. The idler drums are smaller in diameter than the sectioned drums15a, 15b, and 150 so that they do not interfere with the upper run ofthe conveyor 13.

As seen more particularly in FIGURE 3, the conveyor 13 comprises aplurality of perforated sections 21, a Fourdrinier wire 22 which istrained over the perforated sections, and porous dies 23 removablymounted on the perforated sections and wire 22. Each perforated sectionincludes side links 24 and 25 and a perforated platen 27 attached to theside links and extending therebetween. The side links are disposedperpendicular to the longitudinal axes of the sectioned drums 15a, 15band 15c. The end links 24 and 25 of the perforated sections 21 arejoined by pin connectors 29 to provide an endless conveyor 13, andincluding openings 26 which engage teeth on the drums.

Since each of the sectioned drums 15a, 15b, and 150 is constructedsubstantially the same, they will be particularly described withreference to drum 15a and corresponding parts will be similarlynumbered. The sectioned drum 15a comprises a tubular shaft 31 rotatablysupported in journals 32. The drum further comprises polygonal endplates 33 and 35 secured to the shaft and axially extending frames 37located at the periphery of the end plates 33 and 35. Gear-type teeth 41are attached to the frames 37 which engage the openings 26 in the sidelinks 23 and 25 of a perforated section 21.

The frames 3'7 are generally rectangular in shape and are proportionedto accommodate the area of the perfo rated sections 21 of the conveyor13. In operation, the perforated sections provide a cap for the frameswhen the conveyor enters the reservoirs 19m, 1%, and 19c and the frames37 coact with the perforated sections of the conveyor 13 to drive andpull the conveyor through the apparatus of the invention.

The frames 37 of the drum 150, form the outer edges of housings 45. Eachhousing 45 has outwardly-flaring walls 47 attached to the end plates 33and 35 and the frame 37. Each housing 45 connects to a pipe or tube 49at its inner end. The tube 49, in turn, connects to and communicateswith the shaft 31.

The tubular shaft 31 of the drum 15a is in communication with a pump orother vacuum producing means (not illustrated), through a vacuum line58, whereby subatmospheric pressure may be established Within the shaftand in the housings 45. Timed valve means 51 are also provided, wherebythe pressure within the housing 45 may be reduced to subatmosphericpressure in timed relation to the rotation of the drum. The valve means7 51 includes a valve 51a in each tube 49 which is activated by a pinion5112 which engages a fixed gear 510 connected to the journal 32. Thepinions 51b are journalled on the end plate 33 so that as the drum 15arotates, the

3 valve means is actuated in relation to the rotation. The valve means51 is timed so that the valve 51a is open and a subatmospheric pressureis established in the housing 45 when the conveyor 13 is in the stock inthe reservoir 19, and the pressure is released when the conveyor 13 isout of the reservoir.

As illustrated in FIGURE 1, the conveyor 13 is trained around andbetween the sectioned drums 15a, 15b, and 150 and the idler drums 17aand 17b. The idler drums are mounted on solid shafts 52 which arerotatably supported in suitable journals 52a, and polygonal end plates53 secured thereto. Frames 37 are attached to the end plates, and areprovided with teeth 41 which engage the slotted openings 26 in the sidelinks 24 and of the conveyor 13.

As illustrated in FIGURE 2, sectional drums 15a and 15c are driven bydrive means 1%, comprising a motor 18a, and a gear reducer 18b coupledto the hollow shaft 31 of the drum 15c. Drum 15a is driven by a gearedshaft 18c which, in turn, is driven off the journal 32 of drum 150. Thesectioned drums are driven in the direction indicated by the arrows inFIGURE 1.

As before indicated, the apparatus of the invention further comprisesstock reservoirs 19a, 19b, and 15% disposed beneath each of thesectioned drums 15a, 15b, and 15c. Stock is introduced into the stockreservoirs and is continuously maintained at a level therein whereat thebottom portion of each drum is in the stock. The stock may becontinuously recirculated to insure uniformity of composition.

A vacuum box 63 is provided beneath the upper run of the conveyor 13.The vacuum box 63 is disposed beneath the side links 23 and 25 of theperforated sections 21, in closely adjacent relation to the perforatedplatens 27 of the perforated sections.

A press unit is also provided, as illustrated schematically in FIGURES 1and 2, through which the conveyor 13 extends, and in which press rollsas, which may be heated or unheated, are disposed. The press rolls havefaces which are compatible with the conformation of the particularmolded pulp articles being produced.

The Fourdrinier wire 22 (FIGURES 2 and 3) is trained around thesectioned drums'lSa, 15b, and 15c, outside the conveyor 13. The wire 22is disposed between the side links 24 and 25 of the perforated sections21 in overlying relation to the perforated platens 27. The wire may beof a mesh suitable for the deposition of the particular desired pulpthereon. It should be understood that any porous fabric which is capableof functioning in the same manner as a Fourdrinier wire may also beutilized in the practice of the present invention.

Porous dies 23 are provided on each perforated section 21. The dies areattached to the platen 27 of a perforated section 21 in overlyingrelation to the Fourdrinier wire 22. The dies 23 are fabricated from asufficiently porous material to allow passage of Water therethrough. Thedies are shaped to provide the desired molded pulp article, and, in theillustrated apparatus, dies are provided which are suitable for formingegg cartons and pie plates.

As illustrated schematically in FIGURE 2, there is also provided adrying unit 73, and a slitting and cutting unit 75 to provide individualmolded pulp articles.

In operation, stock comprising pulp of the desired type is introducedinto the stock reservoirs 19a, 19b, and 190. In the illustratedapparatus, comprising three stock reservoirs, a 3-ply deposit of pulpmay be obtained. Each of these plies may comprise the same type of pulp,or, alternatively, pulp having different properties may be applied inall or any of the plies.

As the pulp deposition drums 15a, 15b, and 150 are rotated, in thedirection of the arrows, the perforated sections 21 of the conveyor 13are successively submerged in stock contained in the stock reservoirs19a, 19b, and 190. In particular, when a perforated section 21 is atposition A on pulp deposition drum 19a in FEGURE l, the perforatedplaten 2'7 of that perforated section is substantially completelysubmerged in stock. At this point, the pressure within the housing 45which is in contact with that platen is reduced to subatmosphericpressure by timed valve means 51. Stock is thereby forced through theporous dies 69 or 71, the Fourdrinier wire 22., and the perforatedplaten 27. Pulp from the stock is thereby deposited over the porous dieand the Fourdrinier wire in a continuous web.

Subatmospheric pressure is maintained in the housing 45 until theperforated section 21 reaches position B in FIGURE 1, whereupon valvemeans 51 closes valve 51a, and the pressure in the housing returns toambient conditions. It will be seen that pulp is thereby depositedsuccessively upon the porous dies 69 and 71 and the wire 22 to provide acontinuous web which includes molded pulp articles as an integralportion of the web.

Additional plies of pulp are deposited on the die and the wire in likemanner at drums 15b and 150. The web so formed is thence transported bythe conveyor 13 over the vacuum box 63 and into the press unit 65.

In this connection, it may be desirable, under some conditions and withsome pulp articles, to remove a substantial portion of the water fromthe web. Under these conditions, the press rolls disposed in the pressunit 65 are utilized, and the rolls may also be heated to removeadditional water from the web. Under other conditions, and with otherpulp articles, it may be desirable to remove less water from the web,and water removal may be accomplished by the vacuum box alone.

After the desired amount of water has been removed from the web at thevacuum box and press unit 65, the web is removed from the FourdrinierWire 22 and the porous dies 23 and transported to the drying unit 73 andto the slitting and cutting unit 75 to provide individual molded pulparticles. In this connection, the web is lifted at sectioned drum 15a.One method for effecting this lifting comprises the introduction ofcompressed air to a housing 45 of the pulp deposition drum 15a as aperforated section 21 of the conveyor 13 reaches position C in FIGURE 1.The timed introduction of compressed air in this manner may beaccomplished by suitable timed valve means, in accordance with knownmethods and apparatus.

Since the molded pulp articles comprise an integral portion of acontinuous web, they are effectively and etficiently transportable tosubsequent operations and equipment. As an example of the practice ofthe present invention, apparatus illustrated is operated at a conveyorspeed of feet per minute, and the web is transported at this speed tothe drying unit and the slitting and cutting unit '75. Thus, theformation of a continuous web is an important feature of the presentinvention, enabling more rapid and efiicient operation than in pulpforming apparatus heretofore known.

Thus, there is provided improved pulp forming apparatus, on which isformed a continuous web which includes molded pulp articles as anintegral portion thereof. In accordance with the present inventionmolded pulp articles are produced economically and efficiently,resulting in substantial benefits over apparatus heretofore known.

The foregoing description will suggest various modifications to thoseskilled in the art. Such modifications are deemed to be within the scopeof the claims of the present invention.

Various features of the present invention are set forth in the followingclaims.

What is claimed is:

1. Pulp forming apparatus, comprising a plurality of drums, thelongitudinal axes of said drums being generally horizontal andsubstantially parallel to each other, an

endless conveyor trained around and between said drums, said drums beingpartially submerged in stock, said conveyor comprising a plurality ofperforated sections, a porous fabric on said perforated sections, and aporous die on said conveyor in overlying relation to said fabric, drivemeans associated with said drums to rotate said drums and transport saidconveyor, whereby parts of said conveyor are periodically submerge-d instock, vacuum means connected to said partially submerged drums wherebypulp is successively deposited on said porous die and said fabric as acontinuous web during the periods of submergence, and press and dryingmeans to dry the web.

2. Pulp forming apparatus, comprising a plurality of drums, thelongitudinal axes of said drums being generally horizontal andsubstantialy parallel to each other, an endless conveyor trained aroundand between said drums, said drums being partially submerged in stock,said conveyor comprising a plurality of perforated sections, a porousfabric on said perforated sections, and a porous die on said conveyor inoverlying relation to said fabric, drive means associated with saiddrums to rotate said drums and transport said conveyor, whereby parts ofsaid conveyor are periodically submerged in stock, vacuum meansconnected to said partially submerged drums whereby pulp is successivelydeposited on said porous die and said fabric as a continuous web duringthe periods of submergence, press and drying means to dry the web, andcutting and trimming means to provide individual molded pulp articlesfrom the web.

3. Pulp forming apparatus, comprising a plurality of drums, thelongitudinal axes of said drums being generally horizontal andsubstantially parallel to each other, an endless conveyor trained aroundand between said drums, said drums being partially submerged in stock,

said conveyor comprising a plurality of perforated sections, aFourdrinier wire on said perforated sections, and a porous die on saidconveyor in overlying relation to said wire, drive means associated withsaid drums to rotate said drums and transport said conveyor, wherebyparts of said conveyor are periodically submerged in stock, vacuum meansconnected to said partially submerged drums whereby pulp is deposited onsaidporous die and said Fourdrinier wire as a continuous web during theperiods of submergence.

4. The method of manufacturing molded pulp articles comprising the stepsof disposing a porous die having the desired conformation upon anendless porous fabric, conveying the die and the fabric through aquantity of stock while maintaining vacuum conditions on the side of thefabric opposite the die, thereby depositing a layer of pulp on the dieand the fabric to provide a molded pulp article as an integral portionof a continuous web, drying the web on the forming die, and thenseparating the continuous web from the die and fabric, the forming andtransporting of the molded pulp article through the processing stepsbeing conducted while maintaining the die dimensions constant and whileflexing the fabric intermediate the dies.

References Cited by the Examiner UNITED STATES PATENTS 1,661,727 3/28Koppelman et a1. 162-392 1,677,905 7/28 Salisbury 162388 1,719,819 7/29Koppelman 162388 2,592,518 4/52 Magnani 162-367 DONALL H. SYLVESTER,Primary Examiner.

RICHARD D. NEVIUS, WILLIAM B. KNIGHT,

Examiners.

1. PULP FORMING APPARATUS, COMPRISING A PLURALITY OF DRUMS, THELONGITUDINAL AXES OF SAID DRUMS BEING GENERALLY HORIZONTAL ANDSUBSTANTIALLY PARALLEL TO EACH OTHER, AN ENDLESS CONVEYOR TRAINED AROUNDAND BETWEEN SAID DRUMS, SAID DRUMS BEING PARTIALLY SUBMERGED IN STOCK,SAID CONVEYOR COMPRISING A PLURALITY OF PERFORATED SECTIONS, A POROUSFABRIC ON SAID PERFORATED SECTIONS, AND A POROUS DIE ON SAID CONVEYOR INOVERLYING RELATION TO SAID FABRIC, DRIVE MEANS ASSOCIATED WITH SAIDDRUMS TO ROTATE SAID DRUMS AND TRANSPORT SAID CONVEYOR, WHEREBY PARTS OFSAID CONVEYOR ARE PERIODICALLY SUBMERGED IN STOCK, VACUUM MEANSCONNECTED TO SAID PARTIALLY SUBMERGED DRUMS WHEREBY PULP IS SUCCESSIVELYDEPOSITED ON SAID POROUS DIE AND SAID FABRIC AS A CONTINUOUS WEB DURINGTHE PERIODS OF SUBMERGENCE, AND PRESS AND DRYING MEANS TO DRY THE WEB.4. THE METHOD OF MANUFACTURING MOLDED ULP ARTICLES COMPRISING THE STEPSOF DISPOSING A POROUS DIE HAVING THE DESIRED CONFORMATION UPON ANENDLESS POROUS FABRIC, CONVEYING THE DIE AND THE FABRIC THROUGH AQUANTITY OF STOCK WHILE MAINTAINING VACUUM CONDITIONS ON THE SIDE OF THEFABRIC OPPOSITE THE DIE, THEREBY DEPOSITING A LAYER OF PULP ON THE DIEAND THE FABRIC TO PROVIDE A MOLDED PULP ARTICLE AS AN INTEGRAL PORTIONOF A CONTINUOUS WEB, DRYING THE WEB ON THE FORMING DIE, AND THENSEPARATING THE CONTINUOUS WEB FROM THE DIE AND FABRIC, THE FORMING ANDTRANSPORTING OF THE MOLDED PULP ARTICLE THROUGH THE PROCESSING STEPSBEING CONDUCTED WHILE MAINTAINING THE DIE DIMENSIONS CONSTANT AND WHILEFLEXING THE FABRIC INTERMEDIATE THE DIES.